关于mqtt问题

2017-05-04 02:44:10 811 阅读 AI 写同款 · GEO 优化AI 选题数据监测一键分发 ›

ROS中使用mqtt通信：mqtt_bridge 的问题总结第一个问题刚刚使用mqtt_bridge时，可以顺利的从ros发布消息到mqtt，但是当从mqtt发布消息到ROS时一直报错。按原始代码跑MQTT to ROS会在roslaunch的终端上报错unpack(b): extra data。(后来才发现这是msgpack.dumps不能处理字符串格式报错) 通过调试发现是_create_ros_message函数中的 msg_dict = s... 阅读详情

public class MainActivity extends Activity {

private String host = "tcp://119.23.62.18:61616";
private String userName = "admin";
private String passWord = "admin";
private MqttClient client;
private String myTopic = "Market_Data_Info_Topic";
private MqttConnectOptions options;
private ScheduledExecutorService scheduler;

private Handler handler = new Handler() {
@Override
public void handleMessage(Message msg) {
super.handleMessage(msg);
if (msg.what == 1) {
Toast.makeText(MainActivity.this, (String) msg.obj,
Toast.LENGTH_SHORT).show();
} else if (msg.what == 2) {
Toast.makeText(MainActivity.this, "连接成功", Toast.LENGTH_SHORT).show();
try {
client.subscribe(myTopic, 1);
} catch (Exception e) {
e.printStackTrace();
}
} else if (msg.what == 3) {
Toast.makeText(MainActivity.this, "连接失败，系统正在重连", Toast.LENGTH_SHORT).show();
}
}
};

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
init();
startReconnect();
}

private void startReconnect() {
scheduler = Executors.newSingleThreadScheduledExecutor();
scheduler.scheduleAtFixedRate(new Runnable() {
@Override
public void run() {
if (!client.isConnected()) {
connect();
}
}
}, 0 * 1000, 10 * 1000, TimeUnit.MILLISECONDS);
}

private void init() {
try {
String clientId = MqttClient.generateClientId();
//host为主机名，test为clientid即连接MQTT的客户端ID，一般以客户端唯一标识符表示，MemoryPersistence设置clientid的保存形式，默认为以内存保存
client = new MqttClient(host, clientId,
new MemoryPersistence());
//MQTT的连接设置
options = new MqttConnectOptions();
//设置是否清空session,这里如果设置为false表示服务器会保留客户端的连接记录，这里设置为true表示每次连接到服务器都以新的身份连接
options.setCleanSession(true);
//设置连接的用户名
options.setUserName(userName);
//设置连接的密码
options.setPassword(passWord.toCharArray());
// 设置超时时间单位为秒
options.setConnectionTimeout(10);
// 设置会话心跳时间单位为秒服务器会每隔1.5*20秒的时间向客户端发送个消息判断客户端是否在线，但这个方法并没有重连的机制
options.setKeepAliveInterval(20);
//设置回调
client.setCallback(new MqttCallback() {
@Override
public void connectionLost(Throwable throwable) {

}

@Override
public void messageArrived(MqttTopic mqttTopic, MqttMessage mqttMessage) throws Exception {
Message msg = new Message();
msg.what = 1;
msg.obj = mqttTopic + "---" + mqttMessage.toString();
handler.sendMessage(msg);
}

@Override
public void deliveryComplete(MqttDeliveryToken mqttDeliveryToken) {

}
});
// connect();
} catch (Exception e) {
e.printStackTrace();
}
}

private void connect() {
new Thread(new Runnable() {
@Override
public void run() {
try {
StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder()
.permitAll().build();
StrictMode.setThreadPolicy(policy);
if (client != null) {

}
Message msg = new Message();
msg.what = 2;
handler.sendMessage(msg);
} catch (Exception e) {
e.printStackTrace();
Message msg = new Message();
msg.what = 3;
handler.sendMessage(msg);
}
}
}).start();
}

@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
if (client != null && keyCode == KeyEvent.KEYCODE_BACK) {
try {
client.disconnect();
} catch (Exception e) {
e.printStackTrace();
}
}
return super.onKeyDown(keyCode, event);
}

@Override
protected void onDestroy() {
super.onDestroy();
try {
scheduler.shutdown();
client.disconnect();
} catch (MqttException e) {
e.printStackTrace();
}
}

这是我的代码，org.eclipse.paho.client.mqttv3 这是我用的库
老是报：.916 22546-22582/com.activedemotwo W/System.err: 不可识别的包 (32108)
05-04 14:42:16.916 22546-22582/com.activedemotwo W/System.err: at org.eclipse.paho.client.mqttv3.internal.ExceptionHelper.createMqttException(ExceptionHelper.java:27)
05-04 14:42:16.916 22546-22582/com.activedemotwo W/System.err: at org.eclipse.paho.client.mqttv3.internal.wire.MqttInputStream.readMqttWireMessage(MqttInputStream.java:56)
05-04 14:42:16.916 22546-22582/com.activedemotwo W/System.err: at org.eclipse.paho.client.mqttv3.internal.CommsReceiver.run(CommsReceiver.java:86)
05-04 14:42:16.916 22546-22582/com.activedemotwo W/System.err: at java.lang.Thread.run(Thread.java:818)

这是什么原因啊，哪位大神解答哈！感谢！

...全文